U.S. patent number 5,980,256 [Application Number 08/600,893] was granted by the patent office on 1999-11-09 for virtual reality system with enhanced sensory apparatus.
Invention is credited to David E. E. Carmein.
United States Patent |
5,980,256 |
Carmein |
November 9, 1999 |
Virtual reality system with enhanced sensory apparatus
Abstract
The invention provides a motion simulating device which provides
the user with full freedom of motion. Ideally, the motion is
coordinated with the user's senses. The motion simulating device
may include a generally spherical capsule supported by a number of
rollers, at least one of which is a multi-directional active roller
which frictionally engages the spherical capsule. This causes the
spherical capsule to rotate in any desired direction. The capsule
may have mounted within it an interactive solid, which may take the
form of an omni-directional treadmill for supporting the user.
Inventors: |
Carmein; David E. E.
(Bloomington, MN) |
Family
ID: |
26842951 |
Appl.
No.: |
08/600,893 |
Filed: |
February 13, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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401550 |
Mar 10, 1995 |
5562572 |
|
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|
145413 |
Oct 29, 1993 |
5490784 |
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Current U.S.
Class: |
434/55; 434/29;
434/307R; 434/365; 482/902 |
Current CPC
Class: |
A63B
22/02 (20130101); G06F 3/011 (20130101); G09B
9/02 (20130101); G09B 9/10 (20130101); G09B
9/12 (20130101); G09B 9/165 (20130101); A63B
2022/0271 (20130101); B65G 2201/02 (20130101); Y10S
482/902 (20130101); G06F 2203/012 (20130101) |
Current International
Class: |
A63B
22/00 (20060101); A63B 22/02 (20060101); G06F
3/00 (20060101); G09B 9/16 (20060101); G09B
9/02 (20060101); G09B 9/12 (20060101); G09B
9/10 (20060101); G09B 009/00 () |
Field of
Search: |
;434/29,30,34,35,37,38,40,43,45,55,58,59,62,69,118,247,37R,308,365,372
;482/1-9,71,72,52,54,55,57,900-903 ;472/2,17,60,132
;73/379.01,299,323 ;463/1,36 ;345/157,179,302,473,8 ;414/4,5
;348/121 ;198/370.01-370.03,779,371.01-371.03,840 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cheng; Joe H.
Attorney, Agent or Firm: Fredrikson & Byron, PA
Parent Case Text
RELATED APPLICATIONS
The present application is a continuation-in-part of U.S. patent
application Ser. No. 08/401,550 (filed Mar. 10, 1995), now U.S.
Pat. No. 5,562,572, and of U.S. patent application Ser. No.
08/145,413 (filed Oct. 29, 1993), now U.S. Pat. No. 5,490,784.
Claims
What is claimed is:
1. A motion simulating device, comprising:
a capsule adapted to receive at least a portion of a user
therein;
at least three rollers carried by a frame and supportively abutting
the capsule, wherein the capsule is supported solely by the rollers
and at least two of the rollers are active multi-directional
rollers for rotationally driving the capsule with respect to any of
three orthogonal axes located at the center of the capsule; and
a means for interactively controlling the motion of said capsule
and said frame.
2. The motion simulating device of claim 1, wherein the interactive
control means comprises:
a visual display;
a means for sensing the position of said capsule;
a means for coordinating the motion of said capsule and a
representation of motion on said visual display; and
a means for controlling the motion of said capsule responding to a
representation of motion of the user on said visual display.
3. The motion simulating device of claim 2, further comprising:
a means for sensing the position of a user within said capsule;
a means for coordinating the motion of a user and a representation
of motion on the visual display; and
a means for controlling said interactive solids responding to a
representation of the motion of a user on visual display.
4. The motion simulating device of claim 1, wherein the frame
comprises:
plurality of beams;
a plurality of connecting joints, each rigidly attached to two of
said beams; and legs, each connected on one end to one of said
connecting joints and on the other end to a supporting surface.
5. The motion simulating device of claim 4, wherein said connecting
joints further comprise:
beam receptacles, each fixedly attaching one end of said beams to
said connecting joint; and
a mounting plate for fixedly attaching one of said rollers to said
connecting joint.
6. The motion simulating device of claim 4, wherein said actuator
legs further comprise a means for changing the length of said
actuator legs.
7. The motion simulating device of claim 6, wherein said means for
changing the length of said actuator legs further comprises a
hydraulic cylinder for telescoping a movable rod along the
longitudinal axis of a support housing.
8. The motion simulating device of claim 6, wherein said means for
changing the length of said actuator legs further comprises a ball
screw for telescoping a movable rod along the longitudinal axis of
a support housing.
9. The motion simulating device of claim 4, wherein said actuator
legs are each rotatably connected on one end to one of said
connecting joints and on the other end to a supporting surface.
10. The motion simulating device of claim 1, wherein at least one
of said active rollers comprises:
a drive wheel rotatable about a drive axis generally parallel to a
tangent to the surface of said capsule and frictionally engaging
said capsule; and
a yoke for orienting the drive axis with respect to said capsule,
said yoke being pivotable about an axis generally perpendicular to
the drive axis.
11. The motion simulating device of claim 1, wherein there are only
three rollers supportively abutting the capsule and one of said
rollers is passive.
12. The motion simulating device of claim 1, further comprising
active interactive solids connected to the interior of said capsule
for imparting sensations of force directly upon a user.
13. The motion simulating device of claim 12, further comprising a
translatable support arm.
14. The motion simulating device of claim 12, further
comprising:
a support arm;
a back plate attached to said support arm;
abdominal support plates hingedly connected to said back plate;
first limb support plates hingedly connected to said abdominal
support plates;
second limb support plates hingedly connected to said first limb
support plates;
a means for positioning said abdominal support plates, said first
limb support plates, and said second limb support plates, about the
hinged connections; and
a means for securely restraining user to said back plate, said
abdominal support plates, said first limb support plates, and said
second limb support plates.
15. The motion simulating device of claim 14, wherein said support
arm is translatable.
16. The motion simulating device of claim 1 further comprising a
treadmill mounted within the capsule, the treadmill having a track
assembly comprising a user support movable in a first direction for
supporting a user, said user support including a plurality of
support members rotatable about axes generally parallel to the
first direction; a first driver connected to the user support means
to move the user support in the first direction; and a second
driver cooperating with said support members to rotate said
members, whereby the combined movements of the user support and the
support members results in movement of the user on the user support
in a second direction.
17. The motion simulating device of claim 16 wherein the user
support comprises a pair of cylindrical members, at least one
cylindrical member being connected to one of the first and second
drivers to rotate the one cylindrical member; an endless belt
trained about said cylindrical members moveable by the one
cylindrical member in said first direction, said endless belt
having rods for rotatably supporting the user support members for
rotation about axes generally parallel to the first direction.
18. The motion simulating device of claim 17 wherein the second
driver comprises a pair of rollers and an endless belt trained
about said rollers, said second driver being connected to at least
one of the rollers to move the belt; said belt having a top surface
operably engagable with the user support members to rotate said
support members.
19. The motion simulating device of claim 18 wherein said endless
belt has an upper run defining the top surface, further comprising
support means located below said upper run for folding the upper
run in contiguous relationship relative to the user support
members.
20. The motion simulating device of claim 16 wherein the user
support includes rods and the user support members are cylindrical
sleeves rotatably mounted on the rods.
21. The motion simulating device of claim 16 wherein the user
support includes a plurality of longitudinal rods and the support
members comprise spherical members rotatably mounted on the rods
for rotation about the longitudinal axes of the rods.
22. The motion simulating device of claim 16 further comprising a
virtual reality apparatus, the virtual reality apparatus
comprising
a first display mountable on a person's head for displaying visual
images;
a display control means for projection of an image;
a speaker for generating sounds;
a microphone;
means for sensing the position of the person on the support;
and
means connected to the first display, display control means and
speaker for generating images and sounds.
23. The motion simulating device of claim 22 further comprising
interactive solids for providing the person with haptic
feedback.
24. A motion simulating device having an active interactive solid
for use in conjunction with a virtual reality display,
comprising:
a controllably movable physical medium having a sufficient
substance for imparting the desired motion upon a user, the medium
comprising an interactive support apparatus including a support arm
and an interactive pneumatic support suit attached to said support
arm; and
a means for interactively regulating the motion of said physical
medium for regulating the amount and direction of force applied
upon a user.
25. The motion simulating device of claim 24 wherein the support
arm is translatable.
26. The motion simulating device of claim 24, wherein said
regulating means further comprises:
a means for sensing the position of a user;
a means for coordinating the motion of a user and a representation
of the motion of the user on a visual display; and
a means for regulating said controllably movable physical medium
responding to a representation of the motion of the user.
27. The motion simulating device of claim 24 wherein the support
arm is translatable, the interactive pneumatic support suit being
attached to an end of the support arm.
28. A motion simulating device, comprising:
a generally spherical capsule;
a translatable frame for supporting said capsule, the frame
including a plurality of beams, a plurality of connecting joints
each rigidly orienting two of the beams, a plurality of actuator
legs each rotatably connected on one end to one of the connecting
joints and on the other end to a supporting surface;
a plurality of rollers mounted to the connecting joints
supportively abutting the capsule, and at least one of said rollers
comprising an active roller, wherein the active roller comprises a
drive wheel rotatable about a drive axis generally parallel to a
tangent to the surface of said capsule and frictionally engaging
said capsule, and a yoke for orienting the drive axis with respect
to said capsule, the yoke being pivotable about an axis generally
perpendicular to the drive axis;
an interactive user support apparatus including a translatable
support arm connected to an interactive pneumatic support suit;
and
a means for interactively controlling the motion of said capsule
and said frame, the interactive control means including a visual
display, a means for sensing the position of said capsule, a means
for coordinating the motion of said capsule and a representation of
motion on said visual display, a means for sensing the position of
a user within said capsule, a means for coordinating the motion of
a user and a representation of motion on the visual display, a
means for controlling the motion of said capsule and at least one
interactive solid responding to a representation of motion of the
user on said visual display.
Description
FIELD OF THE INVENTION
The present invention generally relates to training and
entertainment devices and provides a device particularly useful in
interactive simulation environments such as are encountered in
flight simulators, computer-based video games, and "virtual
reality" systems.
BACKGROUND OF THE INVENTION
In virtual reality ("VR"), the sensation of motion is coordinated
with the senses of sight, sound, and even touch. The "environment"
that a person experiences is manufactured and contained in the
silicon of computer processors and memory. Flight simulators used
for training professional pilots and astronauts are a type of
virtual reality system commonly in use today. As technology
advances, the applications for "virtual reality" have grown well
beyond such expensive, specialized equipment and are anticipated as
being increasingly common as home entertainment or learning
devices.
Although the hardware and software for generating the audio and
visual components of virtual reality systems has been decreasing in
cost, motion systems for use with such components to complete a
virtual reality system have consistently been prohibitively
expensive. Furthermore, the motion systems are either too complex,
limited in their freedom of motion, or lack adequate
responsiveness.
Various devices have been proposed for generating motion. U.S. Pat.
No. 4,489,932, for example, describes a sphere resting on three
passive casters, with motion of the sphere being actuated either by
the user shifting his weight inside the sphere or by a
multi-directional drive wheel. Another device for generating motion
is found in U.S. Pat. No. 4,545,574, which discloses a sphere
supported by an air stream moving within a large tube where the
sphere is rotatable by louvers directing the force of the air
around the sphere. Although both U.S. Pat. Nos. 4,489,932 and
4,454,574 describe a sphere rotatable about the three orthogonal
axes at the center of the sphere, these devices cannot move the
center of the sphere with respect to the external environment, i.e.
they are not capable of linear motion. Moreover, these devices
described in these patents also lack an interactive system
coordinating motion, sight, and sound.
Other patents have proposed simulated motion devices which
coordinate motion with audio and visual input. U.S. Pat. No.
3,135,057, for example, shows a capsule disposed within heavy
inertial rings offset at 90.degree. from one another. U.S. Pat. No.
4,856,771 shows a system that coordinates motion, video, and sound
by using a cockpit situated inside two rings that are offset by
90.degree. where the rings rest on a rotatable base. U.S. Pat. No.
5,060,932 describes a large gyroscope-like device where various
means of visual and aural stimulations are provided. Although U.S.
Pat. Nos. 3,135,057, 4,856,771, and 5,060,932 describe motion
devices that combine motion with audio and visual input, they all
are limited in their applicability to virtual reality systems
because of their slow response or large expense.
U.S. Pat. No. 4,908,558 describes a spherical motion simulator
mounted on a stationary frame for angular and translational
movement along pitch, roll and yaw axes. Magnetic bearing supported
by the stationary frame provide three degrees of freedom. Drive
means mounted on the stationary frame and connected to the test
unit generate three degrees of freedom of movement.
U.S. Pat. No. 5,071,352 describes a motion platform with limited
translational and rotational motion. An arrangement of three linear
actuators is combined with an A-frame type restraining mechanism to
allow rotation about the pitch and roll axes and along a vertical
axis. A multiple-user capsule sits on a rigid frame and users view
images and experience sound in coordination with motion.
Current devices for simulating motion are cumbersome and expensive.
As a result, the devices have slow response times. Moreover, these
devices are limited in their ability to provide linear and
rotational motion about three orthogonal axes.
A major limitation in state-of-the art VR is the inability to
permit simple walking and running. Navigation is typically
experienced as a disembodied center of consciousness which is
directed by pointing, other gesture or by manipulation of a
joystick, trackball, mouse, or similar device. The actual physical
sensation of walking is limited to one of two forms: a) The user is
restricted to a confined and immobile surface where tracking and
signal generation are well-controlled, and b) the user is confined
to device such as a linear treadmill or wheelchair which transduces
the user's linear motion to virtual space navigation. The
conventional linear treadmill has a movable track which can be
upwardly inclined. The track is only movable in one direction which
restricts motion of the user to the direction of movement of the
track. A monitor, such as a motivational electric display,
associated with the track, records the time, speed, and distance
accomplished by the user.
Use of a linear treadmill, consisting of one continuous moving
track, in conjunction with a monitor permits a user to walk in a
straight line. The user cannot step in arbitrary directions as he
or she would be able to in real life. This limitation in
directionality detracts from the immersive nature of the
experience, and requires that the experience take on more of a
vehicular nature rather than freely walking and navigating
body.
SUMMARY OF THE INVENTION
The present invention provides a mechanical system for creating
motion with six full degrees of freedom; three rotational degrees
of freedom and three linear-translational degrees of freedom. In
its broader aspect, the present invention enables a user to
physically experience full freedom of motion within a limited
space.
In a preferred embodiment, the present invention provides a device
in which the user will experience full freedom of motion in
coordination with the user's senses of sight, hearing, and touch. A
user utilizing the motion simulating device of the present
invention will be able to interact with an electronic environment
using many of the same senses used in the natural world. The
claimed invention enables interaction with an electrically
generated environment by employment of the user's natural center of
balance center and sense of direction.
In its basic form, the motion simulating device consists of a
generally spherical capsule that is supportively abutted by a
number of rollers. At least one of the rollers is a
multi-directional active roller that frictionally engages the
capsule causing the capsule to rotate in any direction. A preferred
embodiment uses three active rollers to impart rotational motion to
the capsule. All rotational modes may be provided by rotating the
sphere upon the rollers.
The linear, or translational, motion is imparted to the capsule by
attaching the rollers to a movable frame. The translational modes
are achieved by using actuator legs capable of moving the frame
along one axis or, more preferably, with respect to three
orthogonal axes.
Optimally, an interactive control means that coordinates sight,
sound, and touch may be operatively connected to the capsule,
active rollers, and frame. Through the interactive control means, a
user may control and respond to a variety of environments and
experience the corresponding motion associated with the user's
control.
One objective of this invention is to enable the user to physically
experience full freedom of motion in a responsive and less
expensive device. Another objective of the invention is to permit a
user to move in coordination with electronic simulation physical
reality.
In accordance with another embodiment of the invention, active
interactive solids and passive interactive solids are incorporated
into a virtual reality system to impart the sensation of touch to
the user. Interactive solids generally may be used to impart
physical confirmation of what the user is touching in the virtual
electronic environment. Active interactive solids are
self-actuating objects operatively connected to the interactive
control means. Active interactive solids may move in coordination
with the electronic simulation of physical reality and physical
input from the user. Passive interactive solids are not
self-activating, and as such, provide physical confirmation of
fixed objects generated in the virtual environment.
An active interactive solid may include an interactive support
apparatus which is disposed within the capsule to impart the
sensation of touch to the user. The interactive support apparatus
includes a translatable support arm connected to a pneumatic
support suit. A user can experience the sensation of support such
as floating in water or other physical activity by imparting
resistive forces to the pneumatic support suit.
The instant invention imparts full rotational freedom while
minimizing the number of moving parts. Such freedom may be
experienced as a "barrel" roll as they fly in a virtually-created
fighter jet, or the tumbling of a virtual car involved in an
end-over-end drivers' training accident.
The present invention efficiently utilizes the relatively low
moment of inertia inherent in a rigid and light spherical
structure. A maximum of rotational acceleration and deceleration is
realized around all axes by utilizing a generally spherical
capsule, minimizing the number and complexity of moving parts, and
generally centering the interior mass.
In another embodiment, the invention employs an interactive solid
which is similar to a linear treadmill in that the user is able to
walk or run in an upright manner and employ proprioceptive sensing
along with balance to imbue a sense of reality to the simulated
environment. Alternatively, the user may assume any manner of
postures with respect to the planar active surface. Other postures
include kneeling, crawling on hands and knees, belly crawling,
sitting and lying prone.
This embodiment of the invention employs an omni-directional
treadmill apparatus that allows a user, such as a person, to walk
or run in any arbitrary direction. The apparatus has a frame for
supporting the apparatus on a fixed surface. A track assembly
mounted on the frame provides a user support that moves in a
direction determined by directional orientation of the user on the
track assembly. The track assembly has a user support movable in
first direction by a first drive motor. The user support means
includes user support members rotatable about axes generally normal
to the direction of movement of the support. A second drive, such
as a power driven endless belt, engages the user support members to
rotate the user support members whereby the combined movement of
the user support members and user supports results in
omni-directional user movement. Controls responsive to the
directional orientation of the user on the user support selectively
control the operation of the first and second drives which in turn
controls the directional user movement to conform with the
orientation of the user on the user support.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a motion simulating device in
accordance with the invention;
FIG. 2 is an elevational view of a motion simulating device in
accordance with another embodiment of the invention;
FIG. 3 is an elevational view of a third embodiment of the present
motion simulating device;
FIG. 4 is a cut-away view of an active roller for use in the
invention;
FIG. 5 is a top view of an alternative active roller in the
invention;
FIG. 6 is a cross-sectional view of another active drive roller in
the invention;
FIG. 7 is a perspective view of an interactive support apparatus in
accordance with the invention wherein the user is in a reclining
position;
FIG. 8 is a perspective view of an alternative interactive support
apparatus, where the user is in a suspended position;
FIG. 9 is a perspective view of yet another interactive support
apparatus which includes translational means;
FIG. 10 is a cut-away view of a motion simulating device with
interactive solids of the invention;
FIG. 11 is a cut-away view of a motion simulating device with
interactive solids in accordance with another embodiment;
FIG. 12 is an elevational view of an interactive solid for
stepping;
FIG. 13 is an elevational view of an interactive support apparatus
coupled to an interactive pneumatic support suit;
FIG. 14 is a cut-away view of the interactive pneumatic support
suit of FIG. 13;
FIG. 15 is a cross-sectional view of a section of the interactive
pneumatic support suit of FIG. 13;
FIG. 16 is a partially broken-away schematic view of a motion
simulating device of the invention including passive interactive
solids;
FIG. 17 is an elevational view of an interactive solid in
accordance with another embodiment of the invention;
FIG. 18 is an elevational view of an interactive solid in
accordance with another embodiment of the invention with a
positioning track;
FIG. 19 is an elevational view of an interactive support apparatus
in accordance with another embodiment of the invention;
FIG. 20 is an elevational view of a motion simulating device of the
invention with high-frequency internal actuators;
FIG. 21 is a perspective view of an omni-directional treadmill in
accordance with a further embodiment of the invention;
FIG. 22 is a block diagram of a motor control for use with the
treadmill of FIG. 21;
FIG. 23 is a perspective view of an alternative embodiment of a
treadmill of the invention;
FIG. 23a is an enlarged sectional view taken along line 23a--23a of
FIG. 23;
FIG. 24 is a perspective view of another embodiment of a treadmill
of the invention;
FIG. 25 is a perspective view of yet another embodiment of a
treadmill of the invention;
FIG. 26 is a diagrammatic view showing a user in real space;
FIG. 27 is a perspective view of a section of a track assembly
employed in the embodiments of a treadmill such as those in FIGS.
21 to 25;
FIG. 28 is another perspective view of a track assembly employed in
the embodiments of a treadmill such as those in FIGS. 21 to 25;
FIG. 29 is a diagrammatic perspective view, similar to FIG. 27,
showing the movement of rotatable sleeves and a sleeve drive
belt;
FIG. 30 is a perspective view of an alternate embodiment of a track
assembly useable with embodiments of treadmills similar to FIGS. 21
to 25;
FIG. 31 is an exploded perspective view of a section of another
embodiment of a track assembly useable with embodiments of
treadmills similar to FIGS. 21 to 25;
FIG. 32 is a perspective view of an embodiment of an
omni-directional wheel and idler rollers;
FIG. 33 is a perspective view of an embodiment of a track assembly
useable with a treadmill similar to FIGS. 21 to 25;
FIG. 34 is a perspective view, partly sectioned, of a spheroid
treadmill segment;
FIG. 35 is a sectional view of a segment of FIG. 34 incorporated in
a track assembly;
FIG. 36 is a perspective view of an alternate embodiment of an
active surface of a track assembly;
FIG. 37 is a perspective view of a treadmill similar to that of
FIG. 24 but including a hexapod motion platform;
FIG. 38 is a perspective view of an active surface haptic display;
and
FIGS. 39a and 39b are diagrammatic views showing how the user at
one site controls a remote device at a distant site.
DETAILED DESCRIPTION OF THE INVENTION
A motion-simulating device (10) embodying the invention is
illustrated in FIGS. 1-3. The device (10) comprises a generally
spherical capsule (20) that rests on at least three rollers, with
one or more active rollers (60) and, optionally, one or more
passive rollers (99). These rollers are attached to a translatable
frame (40).
In a preferred embodiment, a capsule is supportively abutted by
three rollers of which two of the rollers are multi-directional
active rollers. The rollers are then attached to a triangular
platform which is linearly translatable along three orthogonal axes
by six actuator legs. Each apex of the triangular platform is
rotationally connected to two actuator legs and each of the
actuator legs is rotationally connected on the other end to the
ground. The visual and audio input, as well as the responsive
output from the user, are then processed by computers which control
the active rollers and actuator legs.
FIG. 1 shows a capsule (20) having an upper hemisphere (21) and a
lower hemisphere (22). The upper hemisphere (21) and the lower
hemisphere (22) may be hingedly connected at an internal hinge (24)
and open along an equatorial contact line (25). The capsule (20) is
fitted with a chair (26) and a set of full restraint harnesses
(28). A user may receive visual input from a head-mounted visual
display (30) and audio input from earphones (31) or speakers within
the sphere (not shown). In an alternative embodiment, the visual
input may be displayed upon the inner walls of the capsule
(20).
When operating the virtual reality system, the user may control the
motion of the frame (40) and the capsule (20) by a suitable
controller. In the embodiment shown in the drawings, the controller
may comprise two control sticks (32) with each control stick being
capable of controlling three degrees of freedom, as detailed
below.
The translatable frame (40) shown in FIG. 1 has three beams (42)
which are rigidly connected to one another by connecting joints
(44) at beam receptacles (45) to form a triangular platform (41).
Each connecting joint (44) includes a mounting plate (46) for
supporting either an active roller (60) or a passive roller (99).
Each connecting joint (44) is supported by two actuator legs (48).
The actuator legs (48) may each comprise a movable rod (53), a
support housing (52), an actuating motor (50), and a gear reduction
means (51). The movable rod (53) is driven by the actuating motor
(50) so that the movable rod travels along the longitudinal axis of
the support housing (52). The actuator legs (48) are attached to
the connecting joints (44) and to the ground by rotatable
connectors (55). By selectively and differentially moving the
actuator legs (48), the triangular frame (41) can be translated
along any of the three orthogonal axes. Such a construction is
known to those skilled in the art as a Stuart platform. It is
recognized that the movement of the triangular platform (41) may be
effected by a variety of constructions of rigid members, flexible
members, bearings, sliders, motors, and related motion system
components.
The active rollers (60) and the passive rollers (99) are attached
to the connecting joints (44) at the mounting plates (46). In a
preferred embodiment, the capsule (20) is driven by two active
rollers (60) about three orthogonal axes located at the center of
the capsule (20), and a single passive roller (99) rests
substantially upon a thrust bearing (98).
Each active roller (60) includes a drive wheel (70) that is
attached to a rotating yoke (80). The drive wheel (70) is driven by
a drive wheel motor (72) and a reduction means (73). The drive
wheel (70) is rotatable about a drive axis "A--A" that is generally
parallel to a tangent to the surface of the capsule (20). The drive
wheel (70) frictionally engages the capsule (20) and causes the
capsule (20) to rotate in a direction perpendicular to both the
drive axis "A--A" and axis "B--B." The drive wheel (70) is
rotatable about axis "B--B" by rotating the yoke (80). The yoke
(80) is rotatably driven by the yoke motor (81) and a reduction
means (82). In a preferred embodiment, the capsule (20) may be
coated with a friction enhancing substance such as silicon carbide
particles encapsulated by a spreadable liquid binder, or the
surface may be roughened by a light sand blasting to enable faster
rotational acceleration.
The active rollers (60) and the actuator legs (48) are controlled
by an interactive virtual reality control system. The rotational
position of the capsule (20) is measured, e.g., by a gyroscope
(33), and the measurement, e.g., output from the gyroscope, is
routed through an internal computer (34), which may be located
inside the capsule (20). Once position information is processed by
the internal computer (34), the data is optimally sent through a
transmitter (36) to a receiver (37). The receiver (37) then sends
the position data to the main computer (35), which may be located
outside of the capsule (20).
The main computer (35) is also connected to the actuator motor
controllers (57) and the active roller controllers (62). The
actuator motor controllers (57) control the actuator legs (48). The
active roller controllers (62) are connected to the active rollers
(60) by a cable (64). The main computer (35) may also receive
position data from the actuator legs (48) to determine the
translational location of the platform (41).
While using the interactive virtual reality control system, a
head-mounted display adjusts the images it displays in response to
the user's movements. Data entry in the sphere for visual images,
sound, and touch, can use a high-speed digital laser transmission
system having a wide-beam transmitter (38) and a plurality of
capsule receivers (39). Such capsule receivers (39) are evenly
spaced on the outside of the capsule (20). The data entering the
capsule (20) is processed by the internal computer (34) and then
routed to the head-mounted visual display (30) and the earphones
(31). An internal battery (29), which is rechargeable during
periods of non-use and readily replaceable, powers the electrical
system inside the capsule (20). A line voltage supply (58)
connected to a power supply (59) provides the power for the
electrical components located outside of the capsule (20).
FIG. 2 shows an alternative embodiment of the invention employing a
different actuator leg system. The capsule (20) is supported by the
active rollers (60) whose drive means are attached to the
triangular platform (41) through the connecting joints (44). Linear
actuation is achieved by placing the triangular platform (41) on
top of a tripod comprised of three actuator legs (148). Every
connecting joint (44) is supported by a single actuator leg (148).
The actuator legs (148) may have the same structure as the legs
(48) detailed above. Preferably, though, the legs (148) comprise a
ball screw (153) (shown through cutaway), a supporting housing
(152), an actuating motor (150), and a gear reduction means (151).
Rotatable ball joints (155) attach the actuator legs (148) to the
triangular platform (41) and to the ground. The actuator legs (148)
are positioned relative to each other at their centers by a sliding
fastener plate (156) through linear-rotational bearings (157). The
ball screw (153) is held within a smooth-walled upper support
cylinder (154) so that the linear rotational bearings (157) have a
smooth and rigid surface upon which to travel.
As the actuator legs (148) change their lengths, the sliding
fastener plate (156) passively seeks a position that keeps the
tripod of actuator legs (148) rigid and stable. The tripod
arrangement of actuator legs (148) as depicted in FIG. 2 will
impart a known rotation about the vertical axis for any linear
motion transmitted. Such rotation about the vertical axis may be
negated by an equivalent counter-rotation of the capsule (20)
itself. It is recognized that the movement of the triangular
platform (41) may be effected by a variety of constructions of
rigid members, flexible members, bearings, sliders, motors, and
related motion system components.
In FIG. 3, a motion simulating device (210) having four degrees of
freedom is depicted. The motion simulating device (210) retains
full rotational motion, but linear motion is limited to up and
down. In the embodiment shown in FIGS. 1 and 2, communication
between the internal and man computers (24 and 35, respectively) is
accomplished through the transmitter (36) and receiver (37). FIG. 3
illustrates a less expensive, though somewhat more cumbersome,
system using a fixed cable. In this version, rotation around either
horizontal axis is limited by the cable ring (223), which can serve
as a movable means of attachment for a dedicated data exchange and
a power cable (227). The motion simulating device (210) has a
single translational mode which is along its vertical axis. The
active rollers (160) rotate the capsule (220).
In the embodiment of FIG. 3, a user with a head-mounted visual
display (30) is visible through an access port (228) in the upper
hemisphere (221). A single actuator (227), attached to the ground
at one end and an apex-connecting joint (241) at the other end,
provides the single translational motion along the vertical axis.
The apex-connecting joint (241) is connected by rigid supports
(243) to the connecting joints (244). Stability is enhanced by
rigid attachment of the sliding members (249) to the connecting
joints (244). The sliding members (249) are free to move
vertically, but are constrained in all other directions by housings
(252) that are attached rigidly to the ground.
FIGS. 4-6 show a variety of active roller embodiments. FIG. 4
depicts a plan view of an active roller (60) with a single drive
wheel (70). The drive wheel (70) makes frictional contact with the
surface of capsule (20). Rotation of the drive wheel (70) about the
drive axis "A--A" rotates the capsule (20). Rotation of the drive
wheel (70) about a perpendicular axis "B--B" changes the direction
of the drive wheel (70). A yoke assembly (80) houses both the
bearings (71) for the drive wheel (70), and the gear assembly (90)
that actuates the drive wheel (70). A thrust bearing (83) supports
the yoke (80) onto a mounting plate (46), wherein the mounting
plate (46) is contiguous with a connecting joint (44) at the apexes
of the triangular platform (41) as depicted in FIGS. 1-3.
The drive train for rotation about the "A--A" axis begins with a
reversible drive wheel motor (72) and a drive wheel motor reduction
means (73). An output shaft (74) is connected to the drive wheel
motor reduction means (73), and may be coaxial with the control
axis of the reversible yoke motor (81) and a reduction means (82).
The output shaft (74) may emerge into the gear assembly (90)
through the center of the yoke drive gear (84). The drive wheel
drive gear (75) is rigidly connected to the output shaft (74) and
engages a transfer gear (76). The transfer gear (76) may be
connected by a drive shaft (77) through an intermediate bevel gear
(78). The intermediate bevel gear (78) engages the drive wheel
bevel gear (79) which rotates the drive wheel (70) about the drive
axis "A--A."
The reversible yoke motor (81) rotates the yoke (80) and the drive
wheel (70) about axis "B--B" through the reversible motor reduction
means (82). The reversible yoke motor (81) and reduction means (82)
may be substantially hollow along the central axis "B--B" to house
the output shaft (74). Bidirectional torque output from the
reduction means (82) drives the yoke drive gear (84). The yoke
drive gear (84) engages a yoke idler gear (85). The yoke idler gear
(85) engages teeth (86) which may be integral with the yoke (80),
creating a torque that actuates rotation of the yoke (80) and the
drive wheel (70) about the "B--B" axis.
The drive wheel motor (72), drive wheel motor reduction means (73),
reversible yoke motor (81), and reduction means (82) may be rigidly
and coaxially attached together. A face plate (67) mounts the
motor/reducer assembly (95) to the mounting plate (46).
A number of electrical or optical cables (64) may connect the drive
wheel motor (72) and the reversible yoke motor (81) with the power
supply and also carry position information from angular encoders.
This embodiment of an active roller (60) for a single roller about
two perpendicular axes is advantageous because of the fixed
position of the drive wheel motor (72) and the yoke motor (81).
This fixed position allows use of a hard-wired cable harness rather
than expensive and less reliable rolling or sliding electrical
contacts.
FIG. 5 shows an alternative embodiment of the invention employing
an active roller (160) which may have dual drive wheels (170). The
two drive wheels (170) are driven by the output shafts (172). The
output shafts (172) may engage an automotive type differential
(174) which is connected to a gear assembly (190). A thrust bearing
(83) directs loading against the mounting plate (46), which is
formed as part of the connecting joints (44) as shown in FIG. 1.
The motor/reducer assembly (95), as described for FIG. 4, is
connected to the gear assembly (190), and works in the same manner
as described in FIG. 4.
Using two drive wheels (170) for a single active roller (160) is
more advantageous than using a single drive wheel (70) as shown in
FIGS. 1, 2, and 4. First, the rotation of the two drive wheels
(170) about their common center requires less energy input by the
drive wheel motor (72) because the friction of rotation is reduced.
Second, the typical curved path that the common center follows
during actuation generates less friction and thus requires less
energy input by the drive wheel motor (72). Third, the compressive
loading at the contact points on the capsule (20) is half that of a
single drive wheel (70) resulting in less wheel deformation of the
capsule (20) and use of a thinner outer shell for the capsule
(20).
FIG. 6 depicts another embodiment of the invention using a
variation on the single drive wheel active roller system. In FIG.
6, a mounting plate (246) is integral to the connecting joint (44)
as shown in FIG. 1 and rigidly supports both a reversible drive
wheel motor (272) and a reversible motor (281). The drive wheel
motor (272) and the reversible motor (281) may be mounted along two
parallel but separate axis, "B--B" and "C--C". The drive wheel
motor (272) may be connected to a gear assembly (290) so that the
output from the drive wheel motor (272) rotates the drive wheel
(270) about the drive axis "A--A". The drive wheel (270) is
positioned about the "B--B" axis by the reversible motor (281). A
spur gear (286) may be attached to the drive wheel housing (280) to
the drive gear (284) which is connected to the output shaft (285)
of reversible motor (281).
The invention preferably incorporates a vision system which the
user views during motion. The vision system displays a scene on a
monitor or a head mounted display wherein the viewed motion
responds according to the motion of the user's vision. When using a
head-mounted display, the display should shift when the user's head
turns or tilts so that the user's experience parallels that of
turning or tilting his or her head when viewing a real environment.
For example, the displayed horizon will shift upwardly in the
display when the viewer tilts his or her head downwardly. Position
sensing is critical to coordinating vision with motion and the
user's sense of real gravity. Consequently, both the position of
the user's field of vision and the position of the capsule (20)
itself are important in the present invention.
Position sensing may be accomplished by a variety of means.
Rotational position may be sensed by a gyroscope mounted within the
sphere, or by electrical coils interacting through electromagnetic
induction. Linear position may be sensed by linear potentiometers,
linear variable differential transformers, or magnetostrictive
sensors mounted inside the actuator legs (48). Such systems are
well known and well characterized by those in the art of motion
sensing and control.
Motion control of the system may be either closed looped or open
looped. A closed loop system senses the action being controlled and
sends position information back to a controller so that the
controller can minimize the error between the actual performance
and the desired performance. An open loop system, however, does not
send any position information back to the controller, and as a
result, an open loop system does not automatically correct the
error between the actual performance and the desired performance.
Closed-loop motion control is preferred because it is more
accurate. Both closed-loop and open-loop motion controls are
established science, and a variety of theoretical and practical
means are available for their implementation.
A preferred embodiment of the vision system may be a head-mounted
display that sends separate images to each eye. Such a system
creates a true three dimensional effect. Rotational motion on all
three axes with respect to the ground is sensed at the user's head.
Consequently, the user may tip his head and see a tilting landscape
without causing the system to move. One such head-mounted display
adaptable for use with the invention is the Eyephone HRX from VPL
Research, Inc.
Another form of a virtual reality system useful with the present
invention could include sound along with motion and vision. In a
preferred embodiment, the sound system utilizes directional sound
generation. Directional sound generation would allow the user's
ears to perceive sound from different locations giving an
indication of direction. One such system, the Convolvotron, has
been dually developed by NASA's Ames Research Center and Crystal
River Engineering, of Groveland, Calif.
The generally spherical capsule (20) is desirably free to fully
rotate around the three orthogonal axes located at the center, the
capsule has no direct physical contact with any external elements.
Sliding contacts or hardwire cables are not particularly feasible
in the embodiments depicted in FIGS. 1 and 2 because the data cable
(227) shown in FIG. 3, for example, would interfere with the frame
(40) as the sphere is rotated through certain angles or in certain
directions. For example, if the user were to induce motions which
would turn him or her upside down, such as in a simulated roll of
an airplane, the cable system illustrated in FIG. 3 would tend to
abut against the frame or the rollers. Consequently, data in the
embodiments of FIGS. 1 and 2 must be exchanged between the capsule
(20) and the external environment by electromagnetic means, as
mentioned briefly above.
One such electromagnetic means may be a combination of
multi-spectral digital laser pulses sending information into the
capsule (20), and UHF radio signals sending information out of the
capsule (20). For this communication configuration, a laser sending
digital pulses aims its beam toward the capsule (20). A beam
spreader widens the laser beam so that it projects the signal into
a circular area called the "data circle." Laser-sensitive receivers
(not shown) may be spaced evenly over the surface of the capsule
(20) so that at least one receiver is within the data circle at any
time. If necessary, these receivers may be flush with the rest of
the surface of the capsule or be recess-mounted in the surface to
avoid any unwanted effects from contact with the rollers supporting
and driving the capsule.
Inductive means, such as two wire coils, may be used to provide
power inside the capsule (20), where direct connection of power is
not feasible. Alternatively, quick-charge or replaceable batteries
may be employed within the capsule (20).
In addition to the sensations of sight, sound, and movement, the
instant invention may also operate on the basis of the user's sense
of touch by using interactive solids. Interactive solids for use
with the invention are contemplated as being either "passive" or
"active". As used herein, the term "passive interactive solid"
refers to a solid or semi-solid object which remains substantially
stationary or is under the direct physical control of the user,
while the term "active interactive solid" is used to refer to a
solid or semi-solid object which can be moved by the virtual
reality system in coordination with the electronic simulation of
physical reality and physical input from the user.
Passive interactive solids are not connected to the interactive
control means, and as such, move (if at all) only when physically
acted upon by the user. Passive interactive solids may be used to
impart the physical sensations of touch in fixed environments or
corporeal objects that may be simulated by inanimate objects.
For instance, a passive interactive solid may comprise a mock-up of
a control panel which remains fixed within the capsule regardless
of the movements of the user or, in the case of simulated switches
and the like, will move only when the user reaches out and
physically moves the switch. Active interactive solids, in
contrast, are moved within the capsule under the control of the
virtual reality system and may take the form of a solid
representing a wall which moves within the capsule as the user
"moves" within the virtual environment. In an alternative
embodiment having application in the emerging field of so-called
"virtual sex," the visual images displayed for the user may be
explicitly sexual in nature and the active interactive solids may
be solids or semi-solids which represent an interactive partner in
the "virtual sex" environment.
FIGS. 7-8 show an interactive support apparatus (100) which is a
type of active interactive solid. In the present invention, the
interactive support and apparatus (100) is a self actuated solid
that moves in coordination with the virtual vision depicted on the
head-mounted visual display (30) and in response to the physical
contact of the user. The interactive support apparatus (100) may
include a support arm (104) that is attached to the capsule (20). A
back plate (106) may be connected to the support arm (104) and
hingedly attached to abdominal support plates (108) by motorized
hinges (107). Each abdominal support plate (108) may be attached to
two first limb support plates (110), and each first limb support
plates (110) may be attached to a single second limb support plate
(112). The motorized hinges (107) may connect the abdominal support
plates (108), first limb support plates (110), and second limb
support plates (112), so that the user is sufficiently supported
along all parts of his or her body.
Upon entering the capsule (20), the user may simply recline in the
interactive support apparatus (100) and be strapped into place by
the restraints (102) as shown in FIG. 7. The restraints (102) are
preferably placed near major body joints. The user will preferably
be further secured to the interactive support apparatus (100) by a
shoulder harness and groin straps (not shown). The restraints (102)
may be velcro straps, mechanically actuated rigid clamps, or any
other suitable device.
The interactive support apparatus (100) ensures that the user is
supported in a manner appropriate to both the actual physical
environment and the manufactured virtual environment. While
reclining, for example, a user is supported from beneath. An arm
attached to first and second limb support plates (110 and 112,
respectively) will be allowed to move freely above the virtual
surface of reclination. Once the arm attempts to move through the
surface of reclination, however, the support plates become rigid
and the user's arm is prevented from passing through the virtual
surface. In another example, a user may be suspended beneath the
interactive support apparatus (100) and the first and second limb
support plates may provide the sensation of moving a wing through
the air as the user experiences flying like a bird in virtual
space.
FIG. 9 depicts an alternative embodiment of an interactive support
apparatus (100) which is capable of moving along three orthogonal
axes within the capsule (20). In FIG. 9, the actuator arms (348)
and translatable support arm (349) may all be connected on one end
to the capsule (20) by rotatable connectors (355). The actuator
arms (348) may be connected on the other end to the housing (353)
of the translatable support arm (349) by rotatable connectors
(355). The translatable support arm (349) may then be securely
connected to back plate (106).
The actuator arms (348) and the translatable support arm (349) are
depicted as cylinders that may be powered, for example,
hydraulically, pneumatically, or electrically as ball-screw type
actuators. Additionally, the actuator arms (348) and the
translatable support arm (349) may be arranged as a tripod. One
advantage to providing translation back and forth along three
orthogonal axes within the capsule (20) rather than by moving the
frame (40) as shown in FIG. 1 is that the components required for
translational motion within the capsule (20) are smaller in size
and do not require as much power. Moreover, the size of the capsule
(20) will only need to be increased a nominal amount.
FIG. 10 depicts another type of active interactive solid for
simulating walking. As the user's feet rise up and down, either a
first platform (401) or a second platform (402) rise or fall to
meet each step. Similarly, FIG. 11 depicts an active interactive
chair. A seat platform (404) may move into position to act as a
seat while a back platform (403) may move into position to act as a
back. The active interactive solids depicted in FIGS. 10-11 allow a
user to alternatively walk and sit upon a solid support while
staying within the environment of the capsule (20).
FIG. 12 shows an interactive step (400) which moves with respect to
the inner surface of the capsule (20). The interactive step (400)
is also an active interactive solid. A linear actuator (405) may be
mounted on two rotatable axis, "A--A" and "B--B". A foot pad (410)
may be connected to the upper end of the linear actuator (405) and
may be rotatable around axis "C--C" and "D--D". A first lower
stepper motor (407) causes rotation about the "A--A" axis.
Similarly, the second lower stepper motor (406) causes rotation
about the "B--B" axis, the first upper stepper motor (409) causes
rotation about the "C--C" axis, and the second upper stepper motor
(408) causes rotation about the "D--D" axis.
In the virtual reality environment, the interactive step (400) may
simulate stepping up a pathway by first using the lower stepper
motors (407) and (406) to orientate the linear actuator (405) in
the correct direction, and then the upper stepper motors (408) and
(409) rotate the angle of the foot pad (410) to match the
inclination of the expected terrain.
It is understood that a rotation about axis "A--A", "B--B", "C--C",
and "D--D" may be accomplished by a variety of positioning means
known to those skilled in the art of motion control. For example,
any of the stepper motors may be replaced by a servo motor, plain
DC motor, AC motor, hydraulic motor, pneumatic motor, or even a
linear actuator. The linear actuator may be driven by hydraulics,
pneumatics, or electrically. Alternatively, the foot pad (410) may
be placed at the end of a two-part linkage with each joint angle
precisely controlled as depicted in FIG. 10.
FIG. 13 shows another type of active interactive solid, an
interactive fluidic support apparatus (500). The fluidic support
suit may use either a gas or a liquid as the support medium. A
pneumatic support suit (501) may support a user in a suspended
state and uses a gas as the support medium. A buoyancy suit (not
shown) may use a liquid as the support medium. In a pneumatic
support suit, the joints (505) may be mechanically actuated to
respond to the user's positioning requirements. For clarity, FIG.
13 omits depiction of the actuator means at the joints (505),
except as shown by the dual push/pull pistons at the left knee
joint (506). A linear actuator (507) may position the user's body
in response to the user's positioning requirements.
The pneumatic support suit (501) may be attached to one end of the
translatable support arm (349) and the other end of the
translatable support arm (349) may then be attached to the capsule
(20). Two additional actuator arms (348) may be attached to the
translatable support arm (349) by rotatable connectors (355) at the
housing (353).
The cross section of the pneumatic support suit (501) shown in FIG.
13 medium is shown in FIG. 14. The pneumatic support suit (501) may
use a rigid shell (510). An air bladder (512) may be placed
immediately adjacent to the rigid shell (510) on one side and a
semipermeable layer of material (517) on the user's side. A
semirigid porus layer (518) may then be disposed between surface of
the user and the semipermeable layer (517). Air input from a high
pressure supply (514) may be regulated by the control valve (515)
with integral pressure sensing. As the air enters through the
control valve (515), it inflates the bladder (512) to provide
support to the user. The air then passes through the semipermeable
layer (517) and into the highly porus region (518) where it may
then be exhausted out of the system along the exhaust path (519).
The TiNi Alloy Company in San Leandro, Calif., manufactures a valve
suitable for use as the valve on this application.
Relative and absolute positions of key external points of the
pneumatic support suit such as the head, joints, feet, and center
of gravity, may be calculated by kinematic means well known to
those skilled in the art. Additional position information may be
obtained by optical or sonic means.
The air pressure in bladder (512) varies according to the position
of the user with respect to the bladder (512). Position of the user
may be sensed using a sealed chamber (520) which encloses a
pressure sensor (521). FIG. 15 shows a cross section of sensor
location of the pneumatic support suit shown in FIGS. 13 and 14,
with three pressure sensors a first sensor (521), second sensor
(541), and third sensor (561). With the sensors spaced evenly at
120.degree., the position of the user's body may be determined
continuously and accurately. If a supported segment of the user's
body tends to go over to one wall of the suit and away from the
other, one pressure sensing bladder is compressed while the other
expands. For example, as pressure in the first bladder (512)
increases, pressure in either the second bladder (532) or third
bladder (552) may decrease giving direct indication of the position
of the user within the rigid shell (510).
Typically, the first sensor (521), second sensor (541), and third
sensor (561) may be of the micro-machined solid state type
available from a number of manufacturers. The invention permits
attachment of the valves (515) and sensors (521) to the rigid shell
(510) along the surface (511). In the preferred configuration, at
least three sensors may be mounted near every joint (505).
In the present invention, an advantage of an interactive pneumatic
support suit (501) with controlled joint action is that the suit
can be actively employed to create the sensation of virtual solids.
To create a virtual solid, pneumatic support suit (501) will allow
motion up to, but not through the space occupied by a virtual
solid. For example, contact with a solid such as a wall will cause
the pneumatic support suit to lock up so the user cannot push
beyond the virtual plane of the wall, creating the sensation of a
solid wall in a particular location. Similarly, the user may
experience virtual flying like a bird by having the rigid shell
(510) of the pneumatic support suit move and vary the air pressure
in the bladders to transfer the force of the rigid shell to the
user to create the perception of drag and lift against a wing.
The interactive solids require a position sensing system for
providing the correct position in coordination with the virtual
environment depicted on the head-mounted visual display (30). One
example of position sensing system is described above in the
description of the pneumatic support suit (501). Another example of
a position sensing system within the capsule (20) requires a
combination of transmitters and receivers, where a number of
receivers evenly spaced along the inside surface of the capsule
(20) sense the position of a number of transmitters that are
attached to various points of a user.
The transmitter and receivers used in the position sensing system
are well known to those skilled in the art. For example, Logitech,
Inc. uses an ultrasonic technique for determining position in their
2D/6D Mouse. As another example, one could use a magnetic position
sensor such as that marketed under the name "Flock of Birds" by
Ascension Technology Corp. of Burlington, Vt. The Flock of Birds
system may be of limited use if power is supplied to the capsule by
inductive means, as noted above. Also, the PLADAR (Pulsed Light
Angle Direction Tracking And Range) tracking system by David Fenner
of the United Kingdom uses LED transmitter-receiver couplings.
Using the PLADAR system, transmitters may be positioned at points
on a user's body. Three receivers, having an open line of sight to
each sensor, then accurately determine the point in space of each
receiver by triangulating the relative signal strength between the
emitter-receiver pairs as an indication of distance between the
pairs. Consequently, the position of each transmitter may be
determined and then processed to determine the position of the
corresponding body part of a user. The active interactive solids
can respond to a user's requirements for support, suspension, or
free movement, by combining force sensing on the active interactive
solid acting against a user and the position of the user's body
parts as determined by a sensing system such as the PLADAR
light-based system.
A sense of touch may also be achieved by taking advantage of the
fixed nature of certain virtual experiences. Interchangeable
passive interactive solids may be used to tailor the environment
inside the capsule (20) to conform to a specific virtual
experience. In the present invention, passive interactive solids
have no means of self-actuation. Passive interactive solids are
generally pre-formed shapes whose contours match those of the
virtual environment, and may be installed or removed quickly.
Toggle-clamps or the like may be used to speed installation of a
complete passive interactive solid environment.
One example of passive interactive solids involves a "mock-up" of
the interior of an aircraft cockpit. In a cockpit, a pilot views
the components of the cockpit's interior as fixed with respect to
his position while the sky and earth appear to be moving.
Pre-formed shapes whose contours match those of the virtual cockpit
can be installed within the capsule (20) so that a user can press
real buttons, grip a real control stick, and otherwise press
against real solid surfaces corresponding to specific objects
displayed in the virtual environment. Specific detail such as
control gauges which respond to the actions of the user may be
added virtually through the vision system.
FIG. 16 depicts one embodiment of a virtual environment including
passive interactive solids. The user may recline in a fixed chair
(430) which may be fastened to the inner surface of the capsule
(20) by clamps (433). A control panel (440) may house a number of
switches (443) which give an indication of being pressed. The
control panel (440) does not house any dials or gauges, as those
are represented visually through the head-mounted display (30).
By using passive interactive solids, the "reality" that the user
experiences includes all of the elements of a fighter cockpit, for
example, either through actual solid objects or virtual
representations through the head mounted display (30). The passive
interactive solids will allow the user to accurately sense pressing
buttons and flipping switches and the like, and the system may
respond as though the user is pressing real buttons.
An alternative or additional approach to interacting with passive
interactive solids includes a sensing system for sensing the
position of the user's lower arm and hand. Such a sensing system
uses either light or ultrasonics, and may include an emitter (450)
positioned near the users hand and a number of detectors positioned
on the control panel (440) as shown by three detectors (455), (456)
and (457). Position information may then be accurately determined
and an image of the user's hand and arm can be coordinated into the
image projected in the head mounted display (30). For example, a
user will see his or her hand moving toward the control panel (440)
and activating switches (443) when such a sensing system is
employed.
Passive interactive solids are not limited to objects that define a
fixed environment such as chairs and control panels. Passive
interactive solids also include inanimate devices that passively
simulate living beings such animals or humans. For example, a
passive interactive dog may be used to impart the sensation of
touch as a user pets a virtual dog, or a passive interactive human
may be used to impart the sensation of physical contact. Of course,
such objects could also be made as active interactive solids so
that the dog or the partner move independently of direct physical
contact with the user.
FIG. 17 depicts an alternative embodiment of a virtual system of
the invention including a generally human-shaped interactive solid
(691) simulating a human partner. The user (690) may wear a
head-mounted display which displays the position and motion of the
interactive solid (691) in virtual space exactly as the interactive
solid is positioned in real space. This embodiment may be used for
a variety of purposes, such as in teaching dancing lessons in a
virtual reality environment, simulating wrestling, or in "virtual
sex" applications.
The imagery corresponding to the interactive solid (691) may be
completely generated by a computer; and as a result, the user (690)
will have sole control over the virtual interaction. The imagery
corresponding to the interactive solid (691) may also be generated
by input from a second user (not shown) in a separate capsule (not
shown). When the imagery is generated by a second user in a
separate capsule, the interactive solid (691) is controlled by the
second user and optimally is adapted to mimic the motions of the
second user in the confines of the second capsule. Similarly, if
the second user is interacting with a similar interactive solid in
the second capsule, the second interactive solid will be controlled
by the first user (690) and mimic that user's motions.
In FIG. 17, the user (690) may be supported by an interactive
support apparatus (600) similar to the interactive support
apparatus shown in FIG. 9. The interactive solid (691) may also be
supported by an interactive support apparatus (600). An alternate
embodiment of the interactive support apparatus (600) includes a
rotation ring (650) for imparting complete rotation of the
interactive solid (691) about the longitudinal axis of its torso.
The rotation ring (650) permits a variety of interactive
positions.
FIG. 18 depicts an alternative support apparatus (620) of the
present invention for imparting greater freedom of movement to the
interactive solid (691). The interactive support apparatus may
include a linear actuator (624) which is movably attached to a
positioning track (620). The positioning track (620) is mounted to
the inner surface of the capsule at its ends. The linear actuator
(624) moves the interactive solid (691) in and out along the
longitudinal axis of the actuator. The movable contact of the
linear actuator (624) along the arc of the positioning track (626)
enables enhanced positioning of the interactive solid (691). A
rotation ring (650) may be attached to the free end of the linear
actuator to rotate the interactive solid (691) 360.degree. about an
angle relative to the longitudinal axis of a torso of the
interactive solid.
FIG. 19 schematically shows operation of the rotation ring (650)
permitting the user (690) or an interactive solid to move into
alternate positions. The rotation ring (650) may include a fixed
ring (655) which is rigidly connected to the linear actuator (653),
and a moving ring (660) which engages the fixed ring (655) along
its outer surface and support the user with its inner surface. The
moving ring (660) rotates within the fixed ring (655) to permit the
user a full 360.degree. rotation or to impart a full 360.degree. of
motion to an interactive solid (not shown). Any suitable means
known in the art, such as gear and motor assemblies or hydraulics,
may impart the rotation to the moving ring (660).
FIG. 20 depicts an embodiment for a vehicular motion simulator. A
lower hemisphere (22) is supportively abutted by the active rollers
(60) that are connected to the frame (40) as described in FIG. 2.
Four high frequency linear actuators (149) may be connected to the
inside wall of the lower hemisphere (22) and connected to the four
corners of a seat (126). The high frequency motion conveyed by the
high frequency linear actuators (149) to the seat (126) simulates
the high frequency vibrations of a vehicle traveling over a road.
The low frequency motion of the vehicle such as cornering or
acceleration may be provided by the actuators (148) and active
rollers (60).
Given any data exchange format, a user inside the sphere may either
be passive or active. A passive user might put a ROM disk into the
CD disk drive, or interface with a cable television channel. The
user might then be guided through an amusement park ride where such
a ride would have nearly all of the characteristics of a real
ride.
Alternatively, an active user might interface with a dedicated data
link to a central node computer and participate in a continuous
game involving many players operating in their own virtual reality
environment at separate locations. These individual users will each
share the same "virtual space" and could compete or otherwise
interact as if they were in the same physical space. Such
interaction may involve conversations or physical contact such as
dancing.
The invention may also include other means for stimulating a user's
senses such as smell, taste, and temperature. Since the capsule
forms a closed environment, it is within the spirit of the
invention to include stimulating all known senses.
Other types of interactive solid useful in a further embodiment of
the invention are shown in FIGS. 21-39. FIG. 21 depicts an
Omni-Directional Treadmill (ODT)(701) with an active surface (702)
which employs a unique mechanism by which a user (703) positioned
at any location on the active surface may be transported to any
other point on that surface. Typically, a user who is headed off
the active surface is moved back toward the center of the surface
analogous to the way a linear treadmill prevents a user from
running off the front or being flung off the back.
Integral to the ODT is a closed-loop motor control mechanism (704)
and user position-sensing devices (705, 706) which pinpoint the
position of the user (703) with respect to the fixed axes of the
treadmill's active surface. These two work in concert with X axis
control motor (707) and Y axis control motor (708) to ensure proper
positioning of the user on the active surface, which is fixedly
attached at selected points to a rigid base (709). In the
embodiment of FIG. 21, the position sensors are ultrasonic
transducers of a design well known to those skilled in the art of
ultrasonic position sensing.
To address the problem of balance, the ODT optionally includes a
means for steadying the user. A structure as simple as a circular
railing may suffice. More preferable from the standpoint of
transparency is the use of a balance cuff (710) which attaches near
the user's center of balance. A hinge (711) at the small of the
user's back connects the cuff to a support strut (712) which
services to link the user with the X-Y tracking mechanism (713) of
the support frame (714). Under normal circumstances, the cuff
permits active X-Y tracking of the user because the support strut
(712) actively maintains a vertical position. In this fashion, the
user barely knows the cuff is there. When the user becomes
unstable, however, the cuff serves to assist in regaining
balance.
In order for the cuff and strut support to actively track the user
in any orientation, the strut is preferably connected to a support
structure (714) directly over the user's head which is supported by
at least three vertical support members (715). Two motors (716,
717) actuate the X-Y tracking means respectively to maintain the
support strut (712) in a vertical position with respect to the
user. Motors are controlled by sensing the variance of the support
strut from the vertical. A pair of X and Y potentiometers (718)
sense the angular error of the support strut in the XZ plane and YZ
plane respectively. An XZ error, for example, indicates that the X
motor (716) must drive the mechanism in the direction to reduce the
error to zero. Likewise for an error in YZ plane controlling the Y
motor (717). Rotations about Z caused by the user turning are
passed through a slip-ring assembly (719). Said slip-ring assembly
prevents a winding or twisting of the support strut, and also
permits passage of electrical power and signals through rotary
electrical contacts so that connection may be maintained with the
equipment worn by the user. Slip-ring assemblies are readily known
to those familiar with rotary electrical contacts. In a similar
fashion, the vertical motion of the user is permitted by an
extension mechanism (720). Said extension mechanism allows only
linear motion, and permits passage of electrical signals to and
from the user.
The preferred embodiment of the device is a combined ODT/VR system
as revealed in FIG. 21. It allows close coupling of the user's
physical direction and velocity with that of the virtual world in
which the user is navigating. Such a system might typically include
a head-mounted display (HMD) (30) with speakers and microphone,
data glove(s) (722), a body sensing suit (not shown), exoskeletal
joint angle sensors, and/or other related apparatus. Said VR system
would likely include a computer (35) for image generation, sound
generation, and processing of related data such as head and hand
position. Though not explicitly shown, peripherals worn by the user
are hard-wire connected to the computer system through wires
running up the support strut (712), through the X-Y tracking
support (713), and down the support frame vertical member
(715).
The ODT works in synchrony with the VR system by sending velocity
and direction signals to the image generation computer. The
computer uses the velocity vector thus provided to update the image
which is shown to the user so that the user sees a visual image
which takes into account this vector. For example, if the user's
velocity is 1/2 meter/sec in the X direction as indicated by the X
direction motion of the treadmill, the user will observe objects
within the virtual world passing by at 1/2 meter/sec in the minus X
direction.
Alternate embodiments of the combined ODT/VR system include the
ability to tip the platform to stimulate uphill travel, and
networked VR experiences in which one user shares a virtual world
with others. Additional embodiments of the ODT/VR system include
integration of sensing and stimulation systems. Examples of
additional sensing systems might optionally include full or partial
human surface mapping, video capture, or their combination, which
can be manipulated and transported as the user's virtual image. A
companion traveller in virtual space would then see a real-time
facsimile of the user.
FIG. 22 is a block diagram for the control of a single motor. This
motor and its affiliated control loop may actuate either the X or Y
axis control for either the active surface or the support cuff
tracker. With reference to FIG. 22, for a single axis of the active
surface, the control signal is set for zero at the center of the
surface. If the position signal is off-center, the summing junction
generates an error signal which is proportional to the error. A PID
(proportional-integral-differential) controller, which is well
known and well characterized to those familiar with the art of
motion control, is tuned to interpret the error signal over time,
outputting a signal which controls motor velocity along one axis.
Motor velocity and its associated direction are interpreted by the
VR system as a velocity and a direction, and the image presented to
the user is updated accordingly. Motor velocity also causes the
active surface to be driven in a direction which reduces the error.
The plant represents the system components, including the user,
which are responsible for generating a position signal. In the
instant case, the plant includes first, the active surface as it is
driven back toward center; second, the user, who is being driven
back toward center by the motion of the surface; and third, the
ultrasonic transducers, which sense the absolute position of the
user with respect to the zero reference position, and generate the
position signal which may be resolved by the summing junction.
Control of a support cuff tracking motor occurs in a similar
fashion. With reference to FIG. 22, the control signal is set for
zero when the support strut is vertical with respect to its active
axis. If the position signal shows an angle other than zero, an
error signal is generated which is proportional to the angular
error. The PID controller outputs a signal for the motor
controlling the axis of interest, which turns at the specified
velocity. The motor velocity drives the mechanism of the plant in
the direction to reduce the error to zero, and the next cycle is
begun. In the embodiment of FIG. 21, the position signal might be
generated by a rotary potentiometer (718) which is affiliated with
the axis of interest.
An alternative embodiment of the cuff support is shown in FIG. 23.
The user (703) is shown wearing a harness (721) rather than a cuff
(710) of the type shown in FIG. 21. In this case the harness is
flexibly connected through a hinge (711) to a rigid horizontal
member (730). Said member is hingedly connected to a vertical
member (732), which is hingedly connected to a rotating fixture
ring (734). Said ring is rotatably held within the base (724). In
the section view, 23a, we see that the fixture ring is fastened to
a gear ring (736) which rests on a dual bearing race (738)
supported by a bearing ring (740). The gear ring is restrained from
transverse movement by the bearing race grooves, and is constrained
in the upward direction by roller contacts (742). Said ring is
driven about its center by geared contact with a spur gear (744).
The spur gear is driven by the drive motor (746) through a gear
reduction means (748).
Shear sensors within the cuff (750) or at the hinge (711) generate
a signal which is analogous to the error signal of FIG. 22. The
motor (723) drives the ring in a direction to reduce the shear
sensor output toward zero. In this manner the cuff and support
struts track the user's position, providing support and balancing
assistance to the user along with a hard-wired connection to the
HMD and sound system. In all other respects, the active surface
(702) of the ODT behaves the same as that in FIG. 21. For clarity,
the position sensors, motor drivers, and computers are omitted from
the figure.
An alternate embodiment would provide better support for the user
by making the hinge support (752) of the horizontal member (730)
and the hinge support (754) of the vertical member active members,
i.e., they could be actively damped. Active damping would sense the
rate at which the user is moving, and would increase damping in
proportion to the velocity of movement. In this way, if the user
should fall or lose his or her balance, the rapid change in
velocity would cause much increased damping at the hinges, thus
providing the support needed for the user to regain his or her
balance.
A non-motorized embodiment of FIG. 23 would employ a hand grip for
steadying balance, as shown in FIG. 24, rather than the actively
tracking cuff of FIG. 21 or the harness of FIG. 23. The hand grip
(760) attaches through a horizontal member (730) through a hinge
(752) to a vertical member (732). The vertical member is attached
through a hinge (754) to a rotating fixture ring (734) of the type
depicted in FIG. 23 which is rotatably attached to the base (724).
Because the ring rotates around the user (not shown) under power of
the user, there is no motor. The user would always have at least
one hand on the hand grip, and would apply forward and backward
force, and torque to the handle to properly position it as he or
she moved about the active surface (702). This embodiment of the
invention, though reduced in features, would be less costly to
manufacture and would require less ceiling height. The unit could
be comfortably installed in the home or office with no special
height or power requirements. For clarity, the user, position
sensors and computers are omitted from the figure.
Haptic interaction may be accomplished through use of active or
dynamic "interactive solids" also referred to generally as "haptic
displays." FIGS. 25 and 26 show how such haptic display might
interact with the user. FIG. 25 depicts a user in real space. Here
we see the user (703) standing on the ODT (702), supported as
before by a cuff and strut assembly (756). The user is reaching out
and touching a flat, horizontal surface (758) upon which he is
about to sit. Said surface is controllably placed by a motorized
strut assembly consisting of a horizontal member (730), a vertical
member (732), and hinge control motors (764, 766, 768). This
positioning assembly is fixedly mounted on a secondary mounting
ring (734) of the type first shown in FIG. 23. Said ring is powered
and positioned by a motor (723) in a fashion similar to that of the
motor depicted in FIG. 23. The surface of the haptic display (758)
may be controllably placed by suitable rotation of the mounting
ring (734) and turning of the hinge motors (764, 766, and 768).
FIG. 26 depicts visual reality as seen by the user of FIG. 25. In
the virtual space of FIG. 26, the user (703) sees and physically
interacts with the surface of FIG. 25 where it appears as a chair
(772). This is an example of a dynamic interactive solid (also
referred to as an "active interactive solid", above) because it may
dynamically interact with the user to solidify the synthetic visual
reality. A second chair (770) which is within the user's virtual
world is also available to sit upon. If the user were to choose the
second, lower chair, he would simply turn and walk to that chair.
The ring (734) of FIG. 25 will swing the interactive solid (758) to
correspond with the anticipated surface of the second chair (770),
and the user may touch it and sit upon it.
In a similar fashion, a solid may be fixedly placed on the immobile
base of the ODT. This example of a passive interactive solid
performs the same function as a dynamic interactive solid, but has
no ability to move or react to the user or the virtual environment.
The image which corresponds to said passive solid is fixed in the
reference space of both the real world and the virtual world. An
example of said passive solid might be a desktop.
Passive and dynamic solids are not restricted to the circular-ring
embodiments of FIG. 23-26. They may just as easily be implemented
within the embodiment of FIG. 21 and its related variations. An
example of such a hybrid system would include abovemounted cuff
support, such as shown in FIG. 21, as well as single or multiple
rings for positioning and securing passive and dynamic interactive
solids.
The invention is not restricted to the use of a balance cuff. Omni
Directional Treadmills with a larger surface and gentle centering
actions may not need a cuff to support and balance a user. A large
active surface area allows restorative forces to be gentle enough
to avoid upsetting the user's balance.
Interactive solids are referred to in the literature as "haptic
displays" or "roboxels". Related work has evolved interactive
surfaces such as circular plates and shafts with torque feedback
(Good, U.S. Pat. No. 5,185,561). Exoskeletal devices, such as those
developed by Exos, Inc. and by Tachi in Japan, permit force
feedback from shapes of arbitrary geometry. It is in the spirit of
the invention to optionally include both passive and dynamic
interactive, reality-enhancing means as integral to the function of
the ODT.
By itself, the ODT is useful as an exercise device, a motion
analysis device for movement in arbitrary directions, and a
training device for lateral moves in arbitrary direction. Combined
with a VR system, the ODT is useful for exercise, motion analysis,
training, recreation, virtual space navigation, telepresence,
education, and psychological analysis and therapy.
In order for an active surface to move a resting mass in any
direction, it must have available two active vector motion
components, plus and minus X, and plus and minus Y. A linear
treadmill has only plus and minus X. The ODT has both.
The ODT employs a "vector thrust drive" which mechanically
separates the two motion components so that they can be powered and
controlled by two separate motors. The vector thrust is the vector
sum of the X motion component and the Y motion component.
As shown in FIG. 27, the active surface (780) of the ODT,
hereinafter referred to as the roller belt, is comprised of a
multiplicity of identical roller segments (781). A roller segment
consists of a rigid shaft (782) upon which is mounted a freely
rotating roller (783) which is kept within its lateral boundaries
by spring clips (784) fastened at the ends of the shaft. Ends of
the shaft are formed into eye hooks (785), which, in turn, are held
around a common hinge axis by a hinge rod (786). Contact points of
individual eye hooks are separated by spacers (787) to properly
position them and to prevent lateral motion. Each roller
fictionally abuts a surface (788), preferably a flexible belt,
moving at right angles to the motion of the roller segments, along
a line of contact (789) which serves to create selective rotational
motion (790) to the roller. The flexible belt is supportively
abutted by a rigid support plate (791) which substantially takes
the load of the user's weight, and ensures that the active surface
remains flat.
X-direction motion (792) of the roller belt (780) is driven by the
X-direction motor (707) of FIG. 21. Y-direction motion (792) of the
flexible belt (788) is driven by the Y-direction motor (708) of
FIG. 21.
FIG. 28 shows the complete mechanism for achieving full
omni-directional motion, and shows that the hinge rod (801) permits
the roller belt (802) to flex around rollers (803, 804) at the belt
edges. Hex rollers actuate the roller belt in the plus and minus X
vector direction (805). As shown, rollers are hexagonal in shape to
accommodate the hinged nature of the roller belt.
In the embodiment of FIG. 28, one hex roller is powered by a motor
(806) while the other is an idler (807), although both rollers
could easily be powered. The linearly actuated planar surface
(808), which is the top surface of a flat, closed-loop drive belt
(809) is placed in intimate contact with the bottom surface of the
roller belt (810), and oriented so that its motion is at right
angles to the motion of the roller belt. It is supported and
directed at its ends by rollers (811, 812). In the preferred
embodiment, only one roller is actuated by a motor (813); the other
is an idler roller.
Rollers are supported by bearings (814), or by a motor drive shaft
(815). The bottom surface of the flat, flexible drive belt (809) is
supportively abutted by a rigid support plate (816) which is
supported at each of its four comers by support legs (817). Said
support legs, bearings, and motors are securely fastened to a rigid
support surface (818) which serves as ground.
When the roller belt alone is actuated, the top of the rollers
provide plus and minus X motion. When the flat belt alone is
actuated, it fictionally contacts the bottom surface of the
rollers, thus causing them to rotate about their free axis. So, if
the belt is moving in the -Y direction (819), the top surface of
the rollers is moving in the +Y direction (820). Since the contact
lines at the top of each roller are moving in concert, a mass
resting on the active surface (821) defined by the sum of the
contact lines is moved in the direction of the combined X and Y
motion vectors. The active surface of this figure (821) may be
identified with the active surfaces of FIG. 21, FIG. 23, and FIG.
24.
By actuating the beaded belt and the flat belt simultaneously, the
surface contact lines of the rollers may be made to impart any
combination of X and Y movement. For instance, in FIG. 29 we see a
roller segment (830) moving at plus 1 foot/second in the X
direction (831), and the flat belt (832) is moving at minus 1
ft/second in the minus Y direction (833). The freely-rotating
roller converts the belt's -Y motion to a +Y motion at the contact
line (834). And the combined thrust vector (835) equals the vector
sum of the two belt's motions, i.e., 1.414 ft/second at an angle of
45 degrees in the first quadrant.
For better stability, the underside of the flat belt is supported
by a smooth, flat, rigid surface (836). The interface surface
between the flat belt (832) and the support surface (836) is
preferably reduced in friction by coating with a slippery substance
such as teflon.
A tensioning mechanism is advantageously employed on one of the two
rollers in the X direction and one of the rollers in the Y
direction, preferably the idler roller, so that any slack or
relaxation of the belts may be taken up.
Rollers may be arbitrarily small or arbitrarily large. However,
sensible limits are placed on roller size by factors such as ease
of assembly. In addition, the size of the hexagonal rollers is
determined by the length of the roller and the hinge segment it
defines. Obviously, there is an optimal roller size range for said
assembly.
A hexagon shape has been arbitrarily chosen to depict the roller
belt actuation means. The roller is not restricted to this shape,
though it is reasonably expected that the roller will have between
six and eight sides to optimize the balance between size and
manufacturability.
The vector-slip principle may be employed with discrete components
of another form as well. In FIG. 30 is seen one corner of the
active surface of the ODT (841), which consists of a multiplicity
of identical beaded segments (842). A beaded segment consists of a
flexible cable (843) upon which is strung a number of beads (844).
The cable is fastened end to end to form a closed loop. Beads are
separated by spacers (845). Spacers serve two purposes. First, they
ensure a uniform bead spacing. Second, they impart linear force to
the bead as the cable is pulled in either direction. Without the
spacers attached to the cable, the cable would tend to pull through
the beads rather than force them in the desired direction.
Rollers (846) (only one shown) support and direct the return loops
(847) at the segment ends. Adjacent segments are fastened to each
other by the spacer mechanisms (845). The combination of adjacent
bead segments and their associated spacers forms a uniform surface
of beads, which is directly analogous to the uniform surface of the
roller belt. As with the roller belt system, said beads are
actuated in the plus and minus X direction by one set of rollers,
and are actuated in the plus and minus Y direction by contact with
a flat belt (848).
Rather than stringing components on wire and fastening them
together, it is also possible to fabricate a single, repeating
construction unit which accomplishes the same function as the wire
and bead assembly of FIG. 30. FIG. 31 depicts such a repeating
unit. A bead (901) (or roller) is rotatably mounted on a shaft
(902) which has a male (903) and female (904) end as well as a
connecting strut (905). Beads are connected into closed-loop
strings by fastening the male portion of the assembly into the
female. Connections between strings of beads are made by mounting
the hole of the strut (906) over the male portion of the adjacent
string. It is understood that said repeating, componentized
structures are also suitable for construction of a roller-type unit
which duplicates the function of the roller belt described in
connection with FIG. 30.
Following assembly of all the bead segments which comprise a roller
belt, the assembly will look much as that depicted in FIG. 30,
except the spacers (845) will be an integral part of each unit
assembly as separate connecting struts (905).
FIG. 32 reveals yet another embodiment of an omni-directional
surface actuation means which uses a wheel (1001) with idler
rollers (1002) positioned around its circumference. An idler roller
unit (1003) is inserted into the appropriate receptor notch in the
wheel (1001). Each idler axis (1004) is oriented perpendicular to
the powered axis (1005) of the wheel. Said vector-slip wheel has
the unique property of being able to transmit force only through a
line perpendicular to the powered axis (1006), the X axis. Any
motion which the wheel sees in the Y axis passes over the idlers
(1007).
FIG. 33 shows that by combining the above-described vector-slip
wheel of FIG. 32 in an array of X oriented wheels (1101) and Y
oriented wheels (1102), a combined direction vector may be achieved
by selective actuation of the X and Y arrays. Said wheels are
actuated in the Y direction by one set of belts (1103), and in the
X direction by another set of belts (1104) which contact the
bottoms of the wheels. These belts are held and directed by a base
(1105) with guide grooves and mounts for the wheel arrays. Wheel
(1001) is a typical X-direction wheel of the construction of FIG.
32. It is held onto the base by snap fitting its axle (1107) into
snap grooves of a pair of mounting posts (1108), where only one
post is shown. Every wheel is held onto the base in the same
manner.
Because the X wheels are a larger diameter than the Y wheels, the
X-contacting belt and the Y-contacting belt do not come into
contact with one another. As with the beaded invention, actuation
of the X wheel array actuates motion in the plus and minus X
direction which passes easily over the idlers of the Y vector-slip
wheels with no hinderance. Pure Y motion is likewise unhindered by
the X array. As long as a resting mass contacts a reasonable number
of X and Y rollers, combining X and Y wheel arrays permits an
active surface which is able to linearly actuate the resting mass
in any direction through combination of the X and Y vectors.
Drive belts (1103, 1104) are continuous belts which are driven by
rollers (not shown). The rollers are powered and controlled by
motors in a fashion similar to the roller/motor combinations of
FIGS. 21-24 & FIG. 28.
Ergotech, Inc. makes an assortment of large rollers which employ
shaped idler pulleys on their exterior which fall into the same
class as the vector-slip wheel. Their use is as passive moving
devices for boxes and other flat-bottomed articles.
Martin-Marietta has employed a vector-slip drive on a lunar rover.
Their idler rollers are oriented at 45 degrees to the main wheel
drive axis. Thrust is therefore always at 45 degrees to the main
wheel drive axis. By proper combination of the four thrust vectors
available from the four wheels, the rover is able to navigate in
any arbitrary planar direction.
One advantage of the method of discrete construction units is that
their hinged nature allows better control of the active surface
topography. By making the material of the flat belt flexible and
deformable, and by supporting the underside of the flat belt with a
multiplicity of individually controllable idler rollers, each
support point may be selectively raised or lowered. By selectively
raising or lowering the idler support points on the flexible
underside of the flat belt, and by jointedly connecting discrete
construction units to form the beaded active surface, the active
surface may be deformed with controllable bumps and depressions.
Said bumps and depressions might be advantageously shown as
matching bumps and depressions in the virtual environment, thus
enhancing the reality of the immersive experience.
In a comparable fashion, the vector-slip wheels of FIGS. 32 &
33 may be individually raised and lowered to simulate a surface of
varying texture. Since the vector-slip wheels are discrete units
rather than tied in to a belt, they may be raised and lowered
substantially more than their roller or bead counterparts. In this
embodiment, because vector-slip wheels are potentially decoupled
from their support surface, it is no longer possible to drive them
using belts as shown in FIGS. 33. Each wheel must be individually
actuated using separate drive means. While more complex, this
embodiment is the only one of the aforementioned systems which
permits simulation of complex tasks such as climbing stairs while
retaining the advantage of ODT.
FIG. 34 reveals yet another embodiment of an ODT which employs a
moveable, continuous, active surface (1201) that wraps around a
flattened spheroid (1202). Said active surface is held onto the
surface of the spheroid by its own elasticity, and the contact zone
between the rigid spheroid and the moving surface (1203) is
relatively frictionless. By sliding the active surface around the
spheroid, the flat portion at the top of the spheroid (1204) will
serve the same function as the active surface of earlier
figures.
FIG. 35 is a cross section of the fully implemented spheroid
construction of FIG. 34 the ODT (1301) shows an active surface
(1302) which stretchably surrounds the rigid spheroid (1301),
separated by a relatively frictionless layer (1304). The housing
(1305) retains the active surface and spheroid by mounting passive
casters which substantially retain the top (1306) and bottom (1307)
contours of the fundamentally spheroid shape, and by presenting a
slight overhang to retain motion of the assembly in the upward
direction.
The active surface is controllably actuated by frictional contact
with a steerable roller (1308). Said roller is steerable about two
axes. Axis one (1309) is powered by a motor (1310) about the roller
itself, thus driving the bottom side of the active surface by a
frictional contact. Axis two (1311) drive by motor (1312) provides
steerability of the roller so that the roller can direct its thrust
vector in a full circle. A thrust vector provided by the roller
causes the active surface to slide around the spheroid. As
depicted, with the roller providing thrust on the lower surface
substantially in the plus X (1313) direction, the upper surface
responds in the minus X (1314) direction.
FIG. 36 details a potential embodiment of a small area of the
active surface (1401). A pattern of rigid plates is arranged to
form an array of hexagons (1402) and pentagons (1403), much like
the surface of a soccer ball. Corners of the plates are held
together elastically (1404), so that the surface may expand and
contract appropriately as it traverses the spheroid. The underside
of each plate is suitably supported by an arrangement of casters
(1405) which are pressed into the rigid material of the plate. Said
casters permit contact between the plate and the spheroid to be low
in friction, as required for proper function.
An improvement on the embodiment of the powered roller (1308) of
FIG. 35 would be to split the roller function into two rollers
actuated by a differential gear unit. It may still be powered by
two motors as revealed above, however it would gain the advantage
of minimizing rotational friction during steering, in much the same
way an automobile differential permits the drive wheels of a
turning car to rotate at their own speed.
It is understood that the surface construction of FIG. 36 is
exemplary, and represents only one of a class of surface
constructions which fulfills the function of a flexible,
low-friction active surface interacting with a contained,
flattened, spheroid.
Although the basic system configuration includes a support cuff for
assistance of balance and optionally for tracking user orientation,
it also has the potential to completely lift and support the user.
A strengthened and fully actuated support strut connected to a
fully supporting cuff and harness enables a user to be lifted up
from the active surface and moved within the confines of the
mechanically limited motion envelope. A system of this type would
allow a user to transition between active surface locomotion and
free-body flight.
In a similar fashion, the entire active surface and related
mechanism may be mounted upon a motion platform which permits
various combinations of linear and angular motions of the surface.
A tipped surface is useful for simulating an inclined surface in
virtual space, like a user might encounter when walking up a
virtual hill. A surface which moves up and down as well as
angularly can simulate the deck of a ship, or the cabin aisle of an
aircraft.
FIG. 37 depicts the combination of the simplified ODT of FIG. 24
(1501) with a standard 6 degree-of-freedom hexapod motion platform
(1502). The base of the ODT (1503) serves as the attachment point
for the six linear actuators (1504) which comprise the hexapod.
Control of said cylinders provides full 6 DOF motion, and the
control of said hexapod structure is well known to those skilled in
the art of motion control. Cylinders are attached by ball joints
(1505) to the ground, and by ball joints to the base (1503). Said
cylinders may typically be actuated by hydraulics, pneumatics, or
by a ball screw mechanism. The power and control means for the
hexapod and ODT are omitted from the figure, but are understood to
include a power conditioning means, a position sensing means, a
control computer, and a control loop of the type described in FIG.
22. It is also understood that the ODT which attaches to the
hexapod might just as easily be of the construction of FIGS. 21,
23, 25, 30, 33, 34, or 35.
Combining the ODT with an enclosed simulator such as the spherical
motion environment discussed above in connection with FIGS. 1-20
would permit not only 3 to 6 degrees of freedom motion to be
applied to the active surface of the ODT, but would also allow
transitioning between waling, free-body flight, and vehicular
simulation.
An ODT need not be the main interface device for an immersive
system. It might, for example, be complimentary to a vehicle
simulator. A standard simulator for a vehicle such as a jeep,
mounted on a hexapod motion platform, could be placed adjacent to
an ODT. As the user emerges from the vehicle simulator, the ODT
would be positioned at virtual ground so that the user experiences
a smooth transition between vehicular transport and ground
motion.
The unique, omni-directional qualities of an active surface such as
those revealed herein may be employed in yet another way. As a
haptic display device, an active surface is able to convey a sense
of friction to a user as they run their hand along a surface. FIG.
38 presents an embodiment for an active-surface haptic display
(1601). As the user's hand (1602) reaches out to contact a virtual
object, the active surface (1603), which is only slightly larger
than the major diameter of the user's palm print, is placed by a
robotic mechanism (1604) where the user expects that surface to be.
As the user moves their hand along the surface in one vector
direction (1605), the haptic display mirrors the motion of the hand
(1606), while the active surface creates an equal and opposite
counter vector (1607) by moving its surface counter to the motion
of the hand. The user resultingly feels the friction of the virtual
solid's surface as the hand is rubbed across the moving surface.
Because of the omni-directional nature of the active surface, the
hand may trace an arbitrary path.
In its basic embodiment, the active surface is flat both because
the support surface behind the activation means is most easily
fabricated as a flat surface, and because the interlinked nature of
the active means tends to prevent creation of surface contour. A
flat surface will be effective for simulating a flat virtual solid,
but it can only approximate a curved solid. A moderate amount of
curvature may be achieved, however, by bowing the support surface
upward. In the case of haptic display using an active surface,
bowing might be accomplished using pressurized air behind a thin
and flexible support surface. The amount of bowing may be
controlled to correspond to the average curvature at the user's
contact point with the virtual solid.
Description of the preferred embodiment as including an HMD,
gloves, body suit, etc. does not exclude other applicable system
configurations. There are a number of additional display options
which may advantageously employ an ODT. For example, a display
method may surround the user with large display screens. Spherical
display surfaces have been employed for a number of years by
various companies such as IMAX theater, or Evans & Sutherland,
Inc. Most recently, Evans & Sutherland, Inc. revealed a
spherical viewing structure which essentially surrounds the user to
provide a nearly fully spherical viewing surface. A projected image
tracks the user's viewing cone and displays the appropriate scene.
An advanced display method being developed by the Human Interface
Technology Lab places light directly on the retina of the eye using
a weal laster beam. Any of these display systems and their related
interfaces can benefit by use of the ODT.
Discussion of a VR system would not be complete without mention of
telepresence. While VR systems substantially synthesize the user's
sensory experience, telepresence systems extract their sensory
information from a real, remote source and convey it to the senses
of the user. In the simplest example, a pair of video cameras might
be mounted on a 3 degree-of-freedom platform whose motion is slaved
to the user's head. An HMD on the user's head receives the stereo
images from the paired video cameras thus creating the visual
illusion that the user's head is sitting on the platform instead of
the two cameras! A system is this type which also includes sound is
commercially available from Telepresence Research, Inc.
With regards to the ODT, it is feasible to couple the walking
motion of the user to the lateral movement of a remote sensing
device. Using natural walking and turning motion to steer and guide
a remote device has the advantage of freeing both hands to perform
other tasks rather than being restricted to a steering device like
a joystick. A coupling of the telepresent remote with the user
would likely include, besides the ODT, a video and sound link.
Other system configurations might include one or two hand operated
actuators which the operator uses to perform manipulation tasks at
the remote site.
FIGS. 39a and 39b show a system in which a user at one site (FIG.
39a) controls the remote at a distal site (FIG. 39b). This advanced
form of ODT and telepresent coupling would employ not only the
above-mentioned systems, but also a means of conveying the remote's
physical orientation. This is accomplished by using the balance
cuff (710) to force the user (703) into the orientation (1703) of
the remote (1704). Feedback on the cuff by the user, in turn, also
forces the remote into the orientation of the user. By combining
this orientational interplay with a bipedal remote and an
exoskeletal structure (1705) which links the remote's legs to the
user's legs, it is possible for the remote to balance itself in
both standing and walking modes. Combination of the above
structures to enable locomotion of the remote is made possible
because the user is standing on an ODT active surface (702) which
permits the user to employ their natural balance abilities as they
navigate using the electronic eyes of the remote.
According to the provisions of the patent statutes, we have been
explaining the principle, preferred construction and mode of
operation of our invention and have illustrated and described what
we now consider to represent its best embodiments. However, it
should be understood that within the scope of the intended claims,
the invention may be practiced otherwise than as specifically
illustrated and described.
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